The justices ruled unanimously that District of Columbia police were within their rights to arrest 21 partygoers for trespassing and disorderly conduct in 2008 at a boozy bachelor party hosted by a woman named Peaches.

Justice Clarence Thomas wrote that police made an "entirely reasonable inference" that those attending the party, which featured booze, drugs and strippers, knew they shouldn't be there because the home was vacant and in disarray.

"The living room had been converted into a makeshift strip club," he wrote. "Strippers in bras and thongs, with cash stuffed in their garter belts, were giving lap dances. Upstairs, the officers found a group of men with a single, naked woman on a bare mattress — the only bed in the house — along with multiple open condom wrappers and a used condom.

"Taken together, the condition of the house and the conduct of the party-goers allowed the officers to make several 'common-sense conclusions about human behavior.' "

Furthermore, Thomas said, there was the problem of "a bachelor party without a bachelor."

The case is important in setting a precedent for what police can and cannot do when confronted with similar situations. Here, a federal jury awarded $680,000 to the partygoers who sued the district after the arrests, and a federal appeals court upheld the verdict.

While the court's judgment was unanimous, Justices Ruth Bader Ginsburg and Sonia Sotomayor said it need not have backed the police department's version of events.

"The court’s jurisprudence, I am concerned, sets the balance too heavily in favor of police unaccountability to the detriment of Fourth Amendment protection," Ginsburg wrote.

When the case was heard during the first week of the court's 2017 term in October, several justices showed their age. Justice Stephen Breyer, 79, said it's no longer uncommon for young people to show up for a party without knowing all the details — as opposed to during "the Middle Ages, with which I am more familiar."

Justice Elena Kagan, 57, recalled parties she was invited to "long, long ago" where "marijuana was maybe present" and attendees didn't always know the host.

The details were so tantalizing that after nearly an hour's debate, Justice Samuel Alito, 67, asked an obvious question. "Just out of curiosity," he said, "who is the bachelor at this bachelor party?"

Even that was unclear to many celebrants, said their lawyer, Nathaniel Garrett.

"When the officers spoke with Peaches, she was nervous, agitated, and evasive," he wrote. "After initially insisting that she had permission to use the house, she ultimately confessed that this was a lie — a fact that the owner confirmed. Peaches’ lying and evasive behavior gave the officers reason to discredit everything she had told them."